Ideal for activities when the sun is at its strongest high speed red fototec lenses have a light transmission range from 35 12 sharpening contrasts and transitioning from light to dark very quicklycarbon frame fototec lenses with variable tint technology t v adjust rapidly to changing light conditions for superior clarity and protection in bright sun microscopic photochromic particles embedded in the lens react to uv rays darkening the optics so you39ll never squint then with cloud c